Preparing your pet for travel: Crate requirements

Importance of travel crate acclimation

To ensure your pet is accustomed to being in a crate designed for airline travel, which is different from a wire training or sleeping crate, it is extremely important that you obtain the travel crate as far in advance as possible — at least two or three weeks prior to your pet’s travel, though we recommend earlier than that to properly acclimate your pet to their crate. To reduce stress during travel, it is crucial that your pet is comfortable and feels secure in their crate. This process is called “crate acclimation.” Please watch this video for tips on how to acclimate your pet.

Airline-compliant crates

Pets traveling with United PetSafe must use an approved crate that complies with United Airlines requirements, USDA regulations and International Air Transport Association (IATA) standards. United’s crate requirements are based on the USDA and IATA standards.

Approved crates are available for purchase at many pet supply retailers, as well as directly through our partner Petmate at (Use promo code UAFREESHIP at checkout for free shipping of some crate sizes. Shipping is only available within the contiguous U.S.)

It is important to note that while retailers may say a crate is “airline approved,” the crate must meet all the requirements listed below to be accepted for travel with United’s PetSafe program. Compliant crates must be purchased in advance of travel to allow time for proper acclimation.

At check-in, if a crate does not meet United’s requirements or is not the appropriate size for the pet, United will not accept the pet for travel and will require the customer to make alternative arrangements, which may include purchasing a new crate that meets United’s requirements.

Please note that effective June 18, 2018, crates are no longer available for sale or exchange by customers at United PetSafe acceptance facilities.

Crate size

Effective June 18, 2018, United no longer accepts crates that exceed a height of 30 inches for transport via our PetSafe program.

Each crate must:

  • Be large enough for your pet to move freely and stand with their head erect, to turn around and to lie down in a normal position
  • Be tall enough to provide enough room for your pet to stand and sit without their head or ear tips (whichever is higher) touching the top


Please watch this video for information on how to choose the right crate for your pet.

*Not all crate sizes will fit on all aircraft. Please see the standard crate types chart for more details.

Standard crate types

The crate types below are accepted on most United aircraft and are available for purchase through our partner Petmate at

-Standard crate types table
Crate type(#) Crate size (in.) Estimated crate weight (lb.) Aircraft type acceptance
100 21 L x 16 W x 15 H 7 All United aircraft*
200 28 L x 20.5 W x 21.5 H 13 All United aircraft*
300 32 L x 22.5 W x 24 H 18 All United aircraft*
400 36 L x 25 W x 27 H 24 All United aircraft*
500 40 L x 27 W x 30 H 32 All United aircraft*
700   51 No United aircraft

-Standard crate types table

  • Crate size (in.)

    21 L x 16 W x 15 H
  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    All United aircraft*

  • Crate size (in.)

    28 L x 20.5 W x 21.5 H
  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    All United aircraft*

  • Crate size (in.)

    32 L x 22.5 W x 24 H
  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    All United aircraft*

  • Crate size (in.)

    36 L x 25 W x 27 H
  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    All United aircraft*

  • Crate size (in.)

    40 L x 27 W x 30 H
  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    All United aircraft*

  • Crate size (in.)

  • Estimated crate weight (lb.)

  • Aircraft type acceptance


  • Crate size (in.)

  • Estimated crate weight (lb.)

  • Aircraft type acceptance

    No United aircraft

*Crate acceptance guidelines noted above apply to United aircraft – maximum height cannot exceed 30" for any crate. Limitations apply for travel on United Express® flights. The #400 series is the largest crate size accepted on United Express aircraft, and not all United Express aircraft are able to accommodate pet crates. Please call United PetSafe at 1-800-575-3335 to verify availability.

Crate construction

Crate must:

  • Be constructed of rigid plastic, wood or metal sturdy enough to resist bending when firm pressure is applied
  • Have a solid roof with no doors or ventilation openings
  • Have only one door made of metal which must close securely, yet allow pets to be accessible in the event of an emergency
  • Have crate hardware that is in good working condition
  • Have a nut and bolt firmly tightened in each hole that connects the top and bottom of the crate. The bolt must be made of metal. The nut may be metal, nylon or plastic as long as the nut is unbreakable and securely connects the top and bottom of the crate.

The crate must not:

  • Be constructed of plastic that will bend when pressure is applied
  • Have door openings on top, or have more than one door
  • Be made entirely of cardboard, welded or wire mesh, wicker or other collapsible materials
  • Have a plastic or fiberglass door
  • Have side plastic latches, unless additional holes have been drilled and metal bolts have been added to secure the crate
  • Have crate wheels, unless they are removed, locked or firmly taped to prevent the crate from rolling while in transit.

Examples of acceptable crates

Examples of unacceptable crates

Crate ventilation

Each crate must:

  • Have ventilation on three sides for travel within the 50 United States and Puerto Rico
  • Have ventilation on four sides for travel to or from all other locations

Crate limitations

  • Crates cannot be more than 30 inches (76.2 cm) in height. 700 series (Giant) crates are no longer accepted by United Airlines.
  • Crates cannot contain more than one adult cat or dog.
    • A crate may contain two kittens or puppies younger than six months, of comparable size, and weighing less than 20 pounds (9 kg.) each. The crate must allow the kittens or puppies to move about freely.
  • A single crate may not contain both cats and dogs (or kittens and puppies).

Reinforced crates (IATA CR82)

If your dog displays behaviors such as excessive chewing or clawing, even after they are acclimated to a travel crate, United strongly recommends that you use a reinforced crate that complies with specific international requirements (IATA Container Requirement #82) for increased safety. United may also, in its sole discretion, not accept your pet for transport if they persist in excessive chewing, clawing or exhibit any other behavior that shows your pet is not acclimated to the crate.

Reinforced crates must:

  • Be constructed of wood, metal, synthetic materials or weld or wire mesh – materials that cannot be damaged by a pet biting or scratching. Crate cannot contain plastic in any part of its construction
  • Have only one door made of metal, heavy wire mesh or reinforced wood. The door must have a secure fastening that cannot be opened accidentally
  • Comply with crate ventilation requirements
  • Have a leak-proof floor that prevents urine and excreta from escaping the crate
  • Have ventilation openings narrow enough to prevent the pet’s nose or paws from protruding outside the crate

NOTE: Some commercially-made metal crates may be used as reinforced crates; however, custom modifications are often required to ensure that the openings do not allow an animal's nose or paws to protrude outside. Not all crate sizes will fit on all aircraft. Please see the standard crate types chart for more details.